Medial and lateral collateral ligament injuries of the knee

                     Medial and lateral collateral ligament injuries of the knee

                 

                                                            Dr KS Dhillon FRCS

Anatomy of the collateral ligaments

There are two collateral ligaments, one on either side of the knee. The one on the medial side is referred to as the medial collateral and and the other on the lateral side is referred to as the lateral collateral collateral ligament.

Medial collateral ligament

The medial collateral ligament (MCL) has two components, the superficial and the deep components.
The superficial medial collateral ligament has one femoral and two tibial attachments and is the largest structure on the medial aspect of the knee[1]. The proximal femoral attachment is at a round to oval depresion about 3.2 cm proximal and 4.8 cm posterior to the medial femoral epicondyle[1]. There is no attachment between the superficial and deep collateral.
There are two distal attachments of superficial medial collateral ligament.
The attachment of the proximal of the two distal attachments is mainly to soft tissues especially to the anterior arm of the semimembranosus and the distal component has bony attachment anterior to the posteromedial crest of the tibia. The distal component forms the posterior floor of the pes anserine bursa and it also blends with the semimembranosus tendon[1]. Between the two distal attachments pass the inferior medial genicular artery and vein, along with its corresponding nerve branch from the tibial nerve. The average overall length of the superficial medial collateral ligament is  between 10 and 12 cm[1].
The deep medial collateral is formed by thickening of the medial capsule of the knee and it is clearly seen along its anterior border where it is parallel to the superficial collateral. Posteriorly it merges with the central arm of the posterior oblique ligament. It consists of the proximal meniscofemoral and the distal meniscotibial component. It is attached to the meniscus at the joint level and to the medial femoral condyle proximally and the medial tibial plateau distally[1].
The lateral collateral ligament (LCL) is part of a complex of ligaments at the  posterolateral corner of the knee. This complex consists of the LCL, the arcuate ligament, the popliteus ligament, the popliteofibular ligament, the, the short lateral ligament, and the posterolateral joint capsule. Unlike the MCL the LCL is separated from the lateral meniscus by a fat pad.
There appears to be little consensus in the literature regarding the bony attachments of the lateral (fibular) collateral ligament (FCL). Cadaveric dissections and review of the literature by Chappell et al [2] showed that in about half of the instances the proximal attachment is at the apex of the lateral epicondyle and in the other half the attachment is posterior and proximal to the LE. The distal attachment is to lateral aspect of the fibular head by two or three bands [2].The average length of the ligament is about 48.3 mm and the average width is about 4mm [2]. There is a wide variation in the dimensions of the length of ligament reported in the literature varying from 35mm to 72mm [3].

Collateral ligament injuries

Collateral ligament injuries are caused by excessive varus or valgus force applied on the knee with a varus force producing a LCL injury and a valgus force causing a MCL injury. Most patient are able to walk after such injuries and the pain is localised to the medial or the lateral side of the knee. Collateral ligament injuries usually do not produce mechanical (pop, locking) symptoms or symptoms of knee instability. Swelling is usually present over the area of injury and redness may appear after a few days.
Examination shows localised tenderness and swelling at the site of the injury. Tenderness at the proximal or distal attachment may indicate an avulsion injury of the ligament.
Valgus stress testing with the knee in 25-30 º flexion would show laxity when the MCL is torn and varus stress testing with the knee in 20-25 º of flexion would show laxity if the LCL is torn. Laxity on the medial side with knee in extension would indicate a tear of the anterior cruciate ligament (ACL) in addition to the MCL tear. A laxity on the lateral side with the knee in extension would indicate a tear of the posterior capsule and other lateral structures in addition to the LCL tear.
The severity of ligament injury is clinically graded from I to III:

• Grade I - Less than 5 cm laxity (partial tear)
• Grade II - 5-10 cm laxity
• Grade III - More than 10 cm laxity (complete tear)

The diagnosis of collateral tears is always clinical. An X-ray of the knee should however be done to exclude a bony avulsion of the ligament. A varus and valgus stress X ray can be useful for demonstrating ligament laxity. An MRI is usually not needed to make a diagnosis of collateral ligament injury.
An MRI is not very reliable for differentiating grades of injury. Grade 1 injuries usually show periligamentous edema, grade II injuries show partial disruption of the ligamentous structures and grade III injuries show complete disruption of the ligament[4].

Treatment of collateral ligament injuries

All three grades of isolated collateral ligament injuries can be treated conservative with good results. Initially treatment includes cryotherapy, elevation and compression to reduce pain and swelling. Grade I injuries can be treated without a brace while grade II and III injuries are treated with brace and early mobilization. Muscle strengthening exercise are carried out in all patient with ligament injury. The injuries require about 4 to 6 weeks to heal. It may take longer for grade III injuries.
Derscheid et al [5] reported a return to unprotected sports, of football players with Grade I MCL sprains, after an average of 10.6 days and those with grade II sprains after 19.5 days.
Jones et al [6] reported achieving a stable knee in 22 out 24 high school football players with isolated Grade III injuries of the MCL, with conservative treatment. The average recovery time in these patients was 29 days. The players returned to competitive sports at a mean time of 34 days. Similar good outcome of conservative treatment of grade III MCL injuries have been reported by other authors [7,8].
Studies comparing conservative and surgical treatment of grade III MCL tears show that there is no subjective or objective differences between the surgically and non-surgically managed group [9,10]. Bony avulsion injuries, however, benefit from surgical intervention [11].
Chronic valgus instability may result when grade III MCL injuries are inadequately treated and fail to heal. Such instability which affect activities of daily living and affect inability to participate in athletic activities would be an indication for surgical treatment.
Lateral collateral injuries are rare [12] and there is scarcity of literature on the treatment of LCL injuries [13]. Good functional outcome of conservative treatment of grade I and grade II injuries has been reported [14,15]. The numbers of patients in these studies has been very small. Surgery is usually recommended for grade III  posterolateral knee injuries with acute repair of avulsed structures, reconstruction of midsubstance tears [16]. However the number of cases in the published reports has been small and the evidence is therapeutic Level IV evidence. There is a lack of publications comparing operative versus non-operative treatment of grade III LCL injuries. Grade III injuries are often associated with tears of the cruciate ligament which makes treatment more complicated.

Long term outcome of collateral injuries

There is a paucity of literature on the long term outcome of treatment of collateral ligament injuries of the knee.
In 1996 Lundberg and Messner [17] published the long term outcome of treatment of partial medial collateral ligament ruptures. They prospectively followed up 38 patients with partial tears of the MCL. The patients were seen at 3 months, 4 years, and 10 years after the initial trauma. Clinical and radiological examination was carried out. At 4 years follow up the median  Lysholm score was 100 (range, 64 to 100) and 87% of the patients had normal knee function during strenuous activities. At 10 years, the median Lysholm score was 95 (range 73 to 100) and the patients continued to performed on a similarly high activity level as at 4 years. Early signs of osteoarthritis was seen in 13% of the patients but none had joint space reduction.
In 1997 Lundberg and Messner [18] published the 10 years outcome of treatment of isolated and combined medial collateral ligament ruptures. They studied a matched-pair of 40 patients with acute isolated partial medial collateral ligament injury and acute combined medial collateral and anterior cruciate ligament injury. All patients in the first group were treated conservatively and the later group were treated by repair of both ligaments. At 10 years follow up both group of patients had similarly high knee functional Lysholm score and similar activity levels (recreational team sports). There was residual laxity in patients with combined injury. Post traumatic osteoarthritis (OA) was present in half of the knees with combined injuries. There was no OA in patients with isolated injuries. Although the long term functional outcome was good in both groups of patients, the patients with combined injuries had more repeat injuries and more repeat surgeries, increased sagittal laxity, and a higher incidence of radiographic osteoarthritis.
Kannus [19] in 1989 published an average of 8 years follow up of 11 patients with Grade II sprains and 12 patients with Grade III sprains of the lateral collateral ligament who were treated conservatively. He found that the result in Grade II sprains was generally good, despite the fact that some residual laxity persisted. On the other hand in Grade III sprains, the results were not  so good with a high incidence gross lateral laxity, ACL insufficiency, muscle weakness, and posttraumatic osteoarthritis of the injured knee.

Conclusion

The collateral ligaments are the medial and lateral static stabilizers of the knee against varus and valgus stress. The medial collateral injury is the commonest ligament injury to the knee. The ligament injuries are graded into three depending on its severity.Grade I and II injuries are treated conservatively and healing is usually good because of the good vascularity around the ligaments and long term outcome of such injuries is good.
There is controversy, however, with regards to the treatment of grade III injuries. Such injuries are often associated with injury to other structures around the knee and surgical treatment is often recommend. The long term outcome of treatment of grade III injuries is not very good with patients having residual laxity, muscle weakness and OA of the knee in some instances. There is, however, paucity of literature on the long term outcome of treatment of collateral ligament injuries of the knee especially in the recent years.

References

1. LaPrade RF, Engebretsen AH, Ly TV, Johansen S, Wentorf FA, Engebretsen L. The anatomy of the medial part of the knee. J Bone Joint Surg Am. 2007 Sep;89(9):2000-10.
2. Chappell TM, Panchani PN, Moore GD, Tubbs RS, Shoja MM, Loukas M, Kozlowski PB, Khan KH, DiLandro AC, D'Antoni AV. Morphometry of the fibular collateral ligament: anatomic study with comprehensive review of the literature. Clin Anat. 2014 Oct;27(7):1089-96. doi: 10.1002/ca.22416. Epub 2014 May 20.
3. Jun Yan, , Sanjuro Takeda, Kotaro Fujino, Goro Tajima, Jiro Hitomi. Anatomical Reconsideration of the Lateral Collateral Ligament in the Human Knee: Anatomical Observation and Literature Review. Surgical Science. 2012, 3, 484-488.
4. Naraghi AM, White LM. Imaging of Athletic Injuries of Knee Ligaments and Menisci: Sports Imaging Series. Radiology 2016 281:1, 23-40.
5. Derscheid GL, Garrick JG. Medial collateral ligament injuries in football. Nonoperative management of grade I and grade II sprains. Am J Sports Med. 1981;9(6):365–8.
6. Jones RE, Henley MB, Francis P. Nonoperative management of isolated grade III collateral ligament injury in high school football players. Clin Orthop Relat Res. 1986 Dec;(213):137-40.
7. Indelicato PA. Nonoperative management of complete tears of the medial collateral ligament. Orthop Rev. 1989 Sep;18(9):947-52.
8. Indelicato PA, Hermansdorfer J, Huegel M. Nonoperative management of complete tears of the medial collateral ligament of the knee in intercollegiate football players. Clin Orthop Relat Res. 1990 Jul;(256):174-7.
9. Indelicato PA. Non-operative treatment of complete tears of the medial collateral ligament of the knee. J Bone Joint Surg Am. 1983;65(3):323–9.
10. Reider B, et al. Treatment of isolated medial collateral ligament injuries in athletes with early functional rehabilitation. A five-year follow-up study. Am J Sports Med. 1994;22(4):470–7.
11. Wilson TC, Satterfield WH, Johnson DL. Medial collateral ligament “tibial” injuries: indication for acute repair. Orthopedics. 2004;27(4):389–93.
12. DeLee JC, Riley MB, Rockwood CA Acute straight lateral instability of the knee Am J Sports Med. 1983; 11: 404-411.
13. Chahla, J., Moatshe, G., Dean, C., LaPrade, R. Posterolateral Corner of the Knee:Current Concepts. The Archives of Bone and Joint Surgery, 2016; 4(2): 97-103.
14. Kannus P. Nonoperative treatment of grade II and III sprains of the lateral ligament compartment of the knee. Am J Sports Med. 1989; 17(1):83-8.
15. Krukhaug Y, Molster A, Rodt A, Strand T. Lateral ligament injuries of the knee. Knee Surg Sports Traumatol Arthrosc. 1998; 6(1):21-5.
16. Geeslin AG, LaPrade RF. Outcomes of Treatment of Acute Grade-III Isolated and Combined Posterolateral Knee Injuries. A Prospective Case Series and Surgical Technique. J Bone Joint Surg Am. 2011;93:1672-83.
17. Lundberg M, Messner K.Long-Term Prognosis of Isolated Partial Medial Collateral Ligament Ruptures. A Ten-Year Clinical and Radiographic Evaluation of a Prospectively Observed Group of Patients. Am J Sports Med. 1996 Mar-Apr;24(2):160-3.
18. Lundberg M, Messner K. Ten-year prognosis of isolated and combined medial collateral ligament ruptures. A matched comparison in 40 patients using clinical and radiographic evaluations. Am J Sports Med. 1997 Jan-Feb;25(1):2-6.
19. Kannus P. Nonoperative treatment of grade II and III sprains of the lateral ligament compartment of the knee. Am J Sports Med. 1989 Jan-Feb;17(1):83-8.

Lower limb alignment, joint orientation and tibial malunions

              Lower limb alignment, joint orientation and tibial malunions 

                                                           Dr KS Dhillon

What is normal lower limb alignment and joint orientation?

The lower limb alignment is determined by the orientation and shape of the the femur and the tibia as well as the orientation of the hip, knee and ankle joints. The femur and the tibia each has two axis, the mechanical and the anatomical axis.
The mechanical axis runs from the centre of the proximal joint to the centre of the distal joint and this axis remains the same in the sagittal and frontal planes. The anatomical axis on the hand runs through the middle of the diaphysis of the long bone and it can be straight in both planes as in the tibia or it can be straight in one plane (frontal) and curved in another plane (sagittal) as in the femur. For practical purposes the mechanical axis of the lower limb is always considered in the frontal plane.
The angle which is formed between the joint line and the anatomic or mechanical axis is known as the joint orientation angle. The normal lateral distal femur angle (mLDFA) between the femoral mechanical axis and the knee joint line is 87 degrees and between the knee joint line and the femoral anatomical axis (aLDFA) is 81 degrees (79 to 83 degrees).
The medial proximal tibial angle (MPTA) is 87 degrees (85 to 90 degrees) both with the anatomical and mechanical axis because both these axis are the same.
The normal angle between the femoral and tibial mechanical axis was always believed to be 0 degrees. Eckhoff DG et al [1], however, have challenged the ‘concept of a mechanical axis consisting of a straight line through the centers of the femoral head, distal aspect of the femur, and the
talus’.
In a study of the three-dimensional mechanics, kinematics, and morphology of the knee they found that only 2% of individuals have a neutral hip-knee-ankle axis. This is probably due to the the wide variability of the bow in the tibia and femur and the lack of correlation between the bow of the tibia and femur in a given limb. They found that of the 180 subjects studied 57% had a varus angulation at the knee and 40.5% had a valgus angulation. The measurements ranged between 12.2 degrees varus to 15.6 degrees valgus. The median varus however was 2.5 degrees and the median valgus was 1.5 degrees.
Short Xray films of the knee are often used to evaluate the lower limb alignment. Howell et al [2] studied the longitudinal shapes of the tibia and femur and found that they are unrelated and are variable. They measured the angle formed by the anatomic axis of the proximal fourth of the tibia and the mechanical axis of the tibia, as well as the angle formed by the anatomic axis of the distal fourth of the femur and the mechanical axis of the femur and they were able to study the bow of the femur and the tibia in normal individuals.
They found that the angle formed by the anatomic axis and the mechanical axis of both the tibia and femur varied widely and the bow of the tibia and femur varied widely. The angle formed by the tibial mechanical and anatomic axis varied 11 degrees from -4 degrees to 6 degrees. The angle formed by the anatomic and mechanical axes of the femur varied 10 degrees from -1 degree to 8 degrees [2].
The bow of the tibia (the offset of the anatomic axis from the center of the talus) varied 5.7 cm and the bow of the femur (the offset of the anatomic axis from the center of the femoral head) varied 7.2 cm. 
Tang et al [3] found that in the chinese population the angle between the femoral and tibial mechanical axis was not 0 degrees. There was a larger medial inclination of knee joint (varus) in their subjects. Their females had a significantly larger varus alignment of the lower extremity as compared to the caucasian population. They also found that the medial inclination of the tibial plateau was 5.4 ± 2.5 degrees for women and 4.9 ± 2.3 degrees for men which was greater than the commonly reported 3 degrees.
Felson et al [4] did a study to find out if anatomic alignment measured from a knee radiograph can substitute for mechanical alignment from full limb films. They studied 143 subjects who had knee X-rays and full limb films. They found that that the agreement of alignment from knee X-ray to full limb film was only moderate. The anatomic alignment as assessed from the knee radiograph was not exactly the same as the mechanical alignment as measurement from the full limb x-rays. There were knees that were valgus on the knee X-ray that were varus on full limb film and vice versa.

Tibial malunions

The incidence of malunion after treatment of tibial fractures varies between 0% to 31.7% [5]. Court-Brown et al [6] reported a malunion rate of 2.4% in a study of 125 closed and type I open tibial fractures which were treated by nailing. Malunion was defined as shortening of more than 1 cm and or more than 5 degrees of angulation or rotation.
Freedman and Johnson [7] found 12% malalignment in 133 fractures of the tibial treated by nailing. They defined malalignment as 5 degree angulatory deformity in any plane. Malalignment was seen in 58% of proximal third fractures, 7% of middle third fractures, and 8% of distal third fractures.
Bedi et al [8] report a 13.8% incidence of malunion in patients who had treatment for tibial fractures.
Vallier et al [9] reported a 29% incidence of more than 5° of malalignment after nailing as compared with 5.4% after plating of tibial fractures.
Abdel-Salam et al [10] reported a 15.5% incidence of malunions in patients who had plaster cast treatment for tibia fractures. They however defined malunions as angulations of more than 10° or a 2.5 cm or more of shortening.
Jindal [11] reported a malunion incidence of 32% in patients with fracture of the tibia who were treated with a cast.
Wiss et al [12] followed up 101 patients with fracture of the tibia treated by nailing. They found a 4.9% incidence of malunion of the tibia. They defined malunion as an angulation of more than 7° or a more than 1 cm of shortening.
Gregory et al [13] followed up 38 patients with fracture of the tibia treated by nailing and they found a malunion incidence of 7.9%. They defined malunion as angulation of 5° or more and rotation of 10° or more and 1 cm or more of shortening.
A review of literature shows that the criteria for malunion varies, ranging from 5° of varus, valgus, and anterior or posterior angulation, 1 cm of shortening, and 5° of rotation in most studies, to as high as 10° of angulation and 2.5 cm of shortening [5].

Long term outcome of tibia malunion

Good intermediate-term results of treatment of tibial fractures have been reported in majority of the patients in an era when most tibial fractures were treated conservative with a plaster cast [14]. Tibial malunions are more come when fractures are treated with a cast as compared to when they are treated with internal fixation. Tibial malunion has been shown to increase contact stresses in the medial or the lateral compartment of the knee depending on whether it varus or valgus malunion [15]. Similarly contact stress can increase in the ankle when there is malunion of the tibia and there have been suggestions that these increase in stresses can lead to osteoarthritis (OA) of the joints [15,16].
There have been several clinical studies published which showed no association between malunions of the tibia and OA of the knee and ankle [17,18].
Van der Schoot et al [19] on the other hand showed that in patients with more than 5 degree angular malunion of the tibia there was a higher incidence of knee and ankle OA as compared to the uninjured side. They found a significant correlation between symptoms in the knee and arthritis but there was no significant relationship between symptoms and ankle arthritis or malalignment.
A more detailed examination of the paper shows that the clinical outcome at an average follow up of 15 years was good in the patients. They reviewed 88 patients out of 106 who were treated for a fracture of the tibia. They found that 49% of the patients had 5 degrees or more of angular deformity and out of these patients 58% had OA of the knee and or ankle. Thirty-one percent of the patient with no malunion had OA. The incidence of grade 2 to 3 OA was low. For the knee it was 4.5% and for the ankle it was 14.5%. Only 13.5 of the patients had symptoms of the knee or ankle or both. About 6.5% of the patients complained of pain at the fracture site. The relationship for symptoms and OA was significant only for the knee and not for the ankle. There was no mention of further surgery for the OA in this report.
The authors concluded that despite the high incidence of OA, there was no relation between malalignment and clinical symptoms. The OA could also be partly due to trauma to the joints at the time the fracture occurred.
The most comprehensive, though retrospective, report, on the long term outcome of tibial fractures which addresses the the issue of malunions is the one by Milner et al [20].
They assessed 164 patients who had tibial shaft fractures 30 to 43 years prior to the review. The subjects were evaluated with regards to lower limb joint pain, stiffness, and disability (assessed with WOMAC osteoarthritis questionnaire); clinical signs of osteoarthritis; and radiographic evidence of knee, ankle, and subtalar joint OA.
Fifteen percent of the patients reported at least moderate knee pain, 6% at least moderate ankle pain and 13% reported at least moderate disability. They found that knee OA was frequently bilateral. The study showed no significant univariate association between malunions of the tibia and the development of osteoarthritis.
The malalignment was assessed using the mechanical hip-knee-ankle angle outside the normal range of 6.25° of varus to 4.75° of valgus. Overall malalignment was seen in 15% of the subjects (17 patients). In about half of the patients (9 patients) the malalignment was due to the fracture malunion and in the rest (8 patients) the malalignment predated the fracture. Most of the subjects in whom OA was observed had normal overall alignment of the lower limb.
The authors concluded that the outcome of treatment tibial shaft fractures is good at thirty-year follow up despite the fact that mild OA is common. They also concluded that fracture malunion is not the cause of the higher prevalence of symptomatic ankle and subtalar osteoarthritis in the injured limb. Varus malalignment occurs occasionally and may produce OA of the medial compartment of the knee, but other undefined factors, rather than malalignment due to malunion, are responsible for the OA after tibial shaft fractures.
Lefaivre et al (21) reported a 14 years follow up of a  small series of patients with fracture of the tibia who were treated by nailing. They found a 35.4% incidence of OA despite the absence of radiographic malalignment. The incidence of knee OA was 16.1%, ankle OA also 16.1%  and 3.2% of the patients had both knee and ankle OA despite the absence of malunion.

Treatment of tibia malunion

The precise definition of a malunion remains elusive and the limits of deformity which can lead to OA also remains imprecise. A tibial malunion, however, can result in angular, rotational and or transitional deformity as well as shortening or lengthening of the bone. When the deformity and or limb length inequality should be corrected remains unresolved. Generally it is believed that surgical intervention is necessary when there is functional (limp, pain) and or cosmetic disability (mark deformity) [22]. Pain at the knee and ankle due to the malunion is relatively uncommon [23].
Though tibial malunion is quite common, treatment of malunion is not often described and the patient numbers are small in the published reports [23].
There remains little agreement in literature as to the degree of limb length inequality that is clinically significant. Most authors agree that the current indication for lengthening of the lower limb would be a disparity exceeding 5 to 6 cm [24]. Usually limb length inequality of 2 cm or less does not require any treatment because such discrepancies are well tolerate [25]. Limb length inequality of between 2 cm and 5 cm is usually treated with a shoe raise.
Correction of length can be carried out by compression osteotomy for shortening of bone and a distraction osteotomy for lengthening the bone. Large length discrepancies can be corrected by gradual distraction, following a metaphyseal corticotomy, using external fixators. The gradual distraction can also correct angular, rotational and translational deformities.
Angular and rotational deformities are corrected with an osteotomy at the level of the deformity followed by internal or external fixation. Several techniques for correction of tibial malunion have been described which can  achieve excellent results but surgery can be associated substantial risk and recovery time. These risks should be discussed at length with patients when planning such surgery [22].

References

1. Eckhoff DG, Bach JM, Spitzer VM, Reinig KD, Bagur MM, Baldini TH, Flannery NM. Three-dimensional mechanics, kinematics, and morphology of the knee viewed in virtual reality. J Bone Joint Surg Am. 2005;87(suppl 2):71–80.
2. Howell SM, Kuznik K, Hull ML, Siston RA. Longitudinal shapes of the tibia and femur are unrelated and variable. Clin Orthop Relat Res. 2010 Apr;468(4):1142-8.
3. Tang WM, Zhu YH, Chiu KY. Axial alignment of the lower extremity in Chinese adults. J Bone Joint Surg Am. 2000 Nov;82-A(11):1603-8.
4. Felson DT, Cooke DV, Niu J, Goggins J, Choi J, Yu J, Nevitt MC and OAI Investigators Group. Can Anatomic Alignment Measured from a Knee Radiograph Substitute for Mechanical Alignment from Full Limb Films? Osteoarthritis Cartilage. 2009 Nov; 17(11): 1448–1452.
5. Coles CP, Gross M. Closed tibial shaft fractures: Management and treatment and treatment complication. A review of prospective literature. CJS, Vol. 43, No. 4, August 2000.
6. Court-Brown CM, Christie J, McQueen MM. Closed intramedullary tibial nailing. Its use in closed and type I open fractures. J Bone Joint Surg Br. 1990 Jul;72(4):605-11.
7. Freedman E, Johnson EE. Radiographic analysis of tibia fracture malalignment following intramedullary nailing. Clin Orthop 1995; 315:25-33.
8. Bedi A, Le TT, Karunakar MA. Surgical treatment of nonarticular distal tibia fractures. J Am Acad Orthop Surg 2006;14:406-16.
9. Vallier HA, Le TT, Bedi A. Radiographic and clinical comparisons of distal tibia shaft fractures (4 to 11 cm proximal to the plafond): plating versus intramedullary nailing. J Orthop Trauma 2008;22:307-311.
10. Abdel-Salam A, Eyres KS, Cleary J. Internal fixation of closed tibial fractures for the management of sports injuries. Br J Sports Med 1991;25:213-7.
11. Jindal R. Tibial fracture: comparison of complications of different treatment modalities. J Adv Med and Dental Scie Res 2016;4 (6): 171-174.
12. Wiss DA, Stetson WB. Unstable fractures of the tibia treated with a reamed intramedullary interlocking nail. Clin Orthop 1995;315:56-63.
13. Gregory P, Sanders R. The treatment of closed, unstable tibial shaft fractures with unreamed interlocking nails. Clin Orthop 1995; 315:48-55.
14. Nicoll EA. Fractures of the tibial shaft. A survey of 705 cases. J Bone Joint Surg Br. 1964;46:373-87.
15. McKellop HA, Sigholm G, Redfern FC, Doyle B, Sarmiento A, Luck JV Sr. The effect of simulated fracture-angulations of the tibia on cartilage pressures in the knee joint. J Bone Joint Surg Am. 1991; 73:1382-91.
16. Wu DD, Burr DB, Boyd RD, Radin EL. Bone and cartilage changes following experimental varus or valgus tibial angulation. J Orthop Res. 1990; 8:572-85.
17. Merchant TC, Dietz FR. Long-term follow-up after fractures of the tibial and fibular shafts. J Bone Joint Surg Am. 1989;71:599-606.
18. Kristensen KD, Kiaer T, Blicher J. No arthrosis of the ankle 20 years after malaligned tibial-shaft fracture. Acta Orthop Scand. 1989;60:208-9.
19. van der Schoot DK, Den Outer AJ, Bode PJ, Obermann WR, van Vugt AB. Degenerative changes at the knee and ankle related to malunion of tibial fractures. 15-year follow-up of 88 patients. J Bone Joint Surg Br. 1996;78:722-5.
20. Milner SA1, Davis TR, Muir KR, Greenwood DC, Doherty M. Long-term outcome after tibial shaft fracture: is malunion important?  J Bone Joint Surg Am. 2002 Jun;84-A(6):971-80.
21. Lefaivre KA, Guy P, Chan H, Blachut PA. Long-term follow-up of tibial shaft fractures treated with intramedullary nailing. J Orthop Trauma. 2008 Sep;22(8):525-9.
22. Mechrefe AP, Koh EY, Trafton PG, DiGiovanni CW. Tibial malunion. Foot Ankle Clin. 2006 Mar;11(1):19-33, vii.
23. Wu, C. C.; Chen, W. J.; Shih, C. H. Tibial shaft malunion treated with reamed intramedullary nailing: a revised technique. Arch Orthop Trauma Surg. 2000; 120: 152-156.
24. Stanitski DF. Limb-length inequality: assessment and treatment options. J Am Acad Orthop Surg. 1999 May-Jun;7(3):143-53.
25. Gross RH. Leg length discrepancy: how much is too much? Orthopedics.  1978;1(4):307-10.