The aim is to investigate if there is a relation between patellar height and knee flexion angle. For this purpose we retrospectively evaluated the radiographs of 500 knees presented for a variety of reasons.

We measure knee flexion angle using a computer-generated goniometer. Patellar height was determined using computer generated measurement for the selected ratios, namely, the Insall–Salvati (I/S), Caton–Deschamps (C/D) and Blackburne–Peel (B/P) indices and Modified I/S Ratio.

A search of an NHS hospital database was made to identify the knee x rays for patients who were below the age of forty. A senior knee surgeon (DC) supervised three trainee trauma and orthopaedics doctors (HA, JM, ES) working on this research. Measurements were made on the Insall–Salvati (I/S), Caton–Deschamps (C/D) and Blackburne–Peel (B/P) indices and Modified I/S Ratio. The team leader then categorised the experimental measurement of patients’ knee flexion angle into three groups. This categorisation was according to the extent of knee flexion. The angles were specifically, 10.1 to 20, 20.1 to 30, and 30.1 to 40 degrees of knee flexion.

Out of the five-hundred at the start of the investigation, four hundred and eighteen patients were excluded because they had had either an operation on the knee or traumatic fracture that was treated conservatively.

In the unstable patellofemoral joint (PFJ), the patella will articulate in an abnormal manner, producing an uneven distribution of forces. It is hypothesised that incongruency of the PFJ, even without clinical instability, may lead to degenerative changes. The aim of this study was to record the change in joint contact area of the PFJ after stabilisation surgery using an established and validated MRI mapping technique.

A prospective MRI imaging study of patients with a history of PFJ instability was performed. The patellofemoral joints were imaged with the use of an MRI scan during active movement from 0° through to 40° of flexion. The congruency through measurement of the contact surface area was mapped in 5-mm intervals on axial slices. Post-stabilisation surgery contact area was compared to the pre-surgery contact area.

In all, 26 patients were studied. The cohort included 12 male and 14 female patients with a mean age of 26 (15-43). The greatest mean differences in congruency between pre- and post-stabilised PFJs were observed at 0-10 degrees of flexion (0.54 cm² versus 1.18 cm², p = 0.04) and between 11° and 20° flexion (1.80 cm² versus 3.45 cm²; p = 0.01).

PFJ stabilisation procedures increase joint congruency. If a single axial series is to be obtained on MRI scan to compare the pre- and post-surgery joint congruity, the authors recommend 11° to 20° of tibiofemoral flexion as this was shown to have the greatest difference in contact surface area between pre- and post-operative congruency.

Abstract

Abstract

Recognized anatomic variations that lead to patella instability include patella alta and trochlea dysplasia. Lateralization of the extensor mechanism relative to the trochlea is often considered to be a contributing factor; however, controversy remains as to the degree this contributes to instability and how this should be measured. As the tibial tuberosity-trochlear groove (TT-TG) is one of most common imaging measurements to assess lateralization of the extensor mechanism, it is important to understand its strengths and weaknesses. Care needs to be taken while interpreting the TT-TG value as it is affected by many factors. Medializing tibial tubercle osteotomy is sometimes used to correct the TT-TG, but may not truly address the underlying anatomical problem. This review set out to determine whether the TT-TG distance sufficiently summarizes the pathoanatomy, and if this assists with planning of surgery in patellar instability.

Cite this article: Bone Jt Open 2022;3(3):268–274.

Aims

The aim of this study was to determine and compare the congruency of the articular surface contact area of the patellofemoral joint (PFJ) during both active and passive movement of the knee with the use of an MRI mapping technique in both the stable and unstable PFJ.

Patellar instability most frequently presents during adolescence. Congenital and infantile dislocation of the patella is a distinct entity from adolescent instability and measurable abnormalities may be present at birth. In the normal patellofemoral joint an increase in quadriceps angle and patellar height are matched by an increase in trochlear depth as the joint matures. Adolescent instability may herald a lifelong condition leading to chronic disability and arthritis.

Restoring normal anatomy by trochleoplasty, tibial tubercle transfer or medial patellofemoral ligament (MPFL) reconstruction in the young adult prevents further instability. Although these techniques are proven in the young adult, they may cause growth arrest and deformity where the physis is open. A vigorous non-operative strategy may permit delay of surgery until growth is complete. Where non-operative treatment has failed a modified MPFL reconstruction may be performed to maintain stability until physeal closure permits anatomical reconstruction. If significant growth remains an extraosseous reconstruction of the MPFL may impart the lowest risk to the physis. If minor growth remains image intensifier guided placement of femoral intraosseous fixation may impart a small, but acceptable, risk to the physis.

This paper presents and discusses the literature relating to adolescent instability and provides a framework for management of these patients.

Cite this article: Bone Joint J 2017;99-B:159–70.

The implementation of knee arthrodesis has become synonymous with limb salvage in the presence of chronic sepsis and bone loss around the knee. This can be seen in failed trauma surgery or knee arthroplasty as an alternative to trans-femoral amputation. There is no prior literature assessing which factors affect knee arthrodesis using external fixation devices.

Sixteen consecutive patients (four women and twelve men) made up of eleven infected knee implants, three internal fixations of the tibial following fractured tibial plateau as well as 2 infected native joints were identified. The mean age at initial surgery was 56 years (range 25 to 82 years). All procedures were performed under the direct supervision of the limb reconstruction teams using a standard protocol with either a Taylor spatial frame or Ilizarov frame. The patient records, microbiology results and radiographs of all patients who underwent knee arthrodesis at this institution between 1999 and 2010 were reviewed.

Of the 16 patients in this study knee fusion occurred in eleven patients (69%). The five patients where arthrodesis failed all had significant bone loss on the pre-operative radiographs and confirmed at surgery. We found a relationship between a significant infection of the knee with MRSA and failure to fuse. Three of the five patients had MRSA isolated from inside the knee at some stage during their treatment.

The five patients where fusion failed were on average older (mean age 63 years against 51 years) and had more extensive bone loss. Those who failed to fuse had more co-morbidities. We would conclude that where there is little or no bone loss, arthrodesis of the knee can be reliably achieved with the use of circular frame fixation. A greater number of negative factors also prolongs the amount of time spent in the external fixator. The presence of significant bone loss, infection, increased age and multiple co-morbidities requires careful evaluation and consideration of trans-femoral amputation as an alternative.

There is a lack of information about the association between patellofemoral osteoarthritis (PFOA) and both adolescent Anterior Knee Pain (AKP) and previous patellar dislocations.

This case-control study involved 222 participants from our knee arthroplasty database answering a questionnaire. 111 patients suffering PFOA were 1:1 matched with a unicompartmental tibiofemoral arthritis control group. Multivariate correlation and binary logistic regression analysis was performed, with odds ratios (ORs) and 95% confidence intervals (CIs) calculated. This analysis helps us assess the effect of both variables whilst adjusting for major confounders, such as previous surgery and patient-reported instability.

An individual is 7.5 times more likely to develop PFOA if they have suffered adolescent AKP (OR 7.5, 95% CIs 1.51–36.94). Additionally, experiencing a patellar dislocation increases the likelihood of development of PFOA, with an adjusted odds ratio of 3.2 (95% CIs 1.25–8.18). A 44-year difference in median age of first dislocation was also observed between the groups.

This should bring into question the traditional belief that adolescent anterior knee pain is a benign pathology. Patellar dislocation is also a significant risk factor. These patients merit investigation, we encourage clinical acknowledgement of the potential consequences when encountering patients suffering from anterior knee pain or patellar dislocation.

Rupture of the pectoralis major (PM) tendon is a rare yet severe injury. Several techniques have been described for PM fixation including a transosseus technique, when cortical buttons are placed at the superior, middle and inferior PM tendon insertion positions. The concern with this technique is the risk that bicortical drilling poses to the axillary nerve as it courses posteriorly to the humerus.

This cadaveric study investigates the proximity of the posterior branch of the axillary nerve to the drill positions for transosseus PM tendon repair. Drills were placed through the humerus at the superior, middle and inferior insertions of the PM tendon and the distance between these positions and the axillary nerve, which had previously been marked, was measured using computed tomography (CT) imaging.

This investigation demonstrates that the superior border of PM tendon insertion is the fixation position that poses the highest risk of damage to the axillary nerve.

Caution should be used when performing bicortical drilling during cortical button PM tendon repair, especially when drilling at the superior border of the PM insertion. We describe ‘safe’ and ‘danger’ zones for transosseus drilling of the humerus reflecting the risk posed to the axillary nerve.

The aim of this study is to document the outcome of a large cohort of patients treated with the Bereiter trochleoplasty with between 1 and 12 years of follow up.

215 consecutive cases in 186 patients were recorded prospectively. All patients were offered yearly clinical and radiological review. PROMs were recorded including the IKDC, OKS, Kujala and SF-12. Patients unable to attend clinic were assessed with PROMS and radiographs from their local institutions where possible.

There were 133 females and 53 males, with a mean age of 21 (14–38). There were no infections and only 6 patients reported further dislocations. There was one flap breakdown and no identified cases of secondary osteoarthritis. PROMs were available for 194 cases in 167 patients (90% follow up). 84% of patients were satisfied, 87% felt their symptoms had improved and 69% had gone back to sport. All scores improved (all p<0.001) except for the SF-12 mental score (p=0.42), with averages comparable to the results of MPFL reconstruction.

Good outcomes were observed despite the difficult patient population in which these cases were performed. The Bereiter trochleoplasty is an effective method of treating recurrent patella instability in patients with severe trochlea dysplasia.

Reported rates of dislocation in hip hemiarthroplasty (HA) for the treatment of intra-capsular fractures of the hip, range between 1% and 10%. HA is frequently performed through a direct lateral surgical approach. The aim of this study is to determine the contribution of the anterior capsule to the stability of a cemented HA through a direct lateral approach.

A total of five whole-body cadavers were thawed at room temperature, providing ten hip joints for investigation. A Thompson HA was cemented in place via a direct lateral approach. The cadavers were then positioned supine, both knee joints were disarticulated and a digital torque wrench was attached to the femur using a circular frame with three half pins. The wrench applied an external rotation force with the hip in extension to allow the hip to dislocate anteriorly. Each hip was dislocated twice; once with a capsular repair and once without repairing the capsule. Stratified sampling ensured the order in which this was performed was alternated for the paired hips on each cadaver.

Comparing peak torque force in hips with the capsule repaired and peak torque force in hips without repair of the capsule, revealed a significant difference between the ‘capsule repaired’ (mean 22.96 Nm, standard deviation (sd) 4.61) and the ‘capsule not repaired’ group (mean 5.6 Nm, sd 2.81) (p < 0.001). Capsular repair may help reduce the risk of hip dislocation following HA.

Cite this article: Bone Joint J 2015;97-B:141–4.

The trapeziometacarpal joint (TMJ) is the most commonly involved arthritic joint in the hand and is often injected in the outpatient setting. This study assesses the accuracy of TMJ injections.

Six pairs of thawed, fresh-frozen cadaveric upper limbs were placed in the anatomic position. The limbs were randomized to be injected by one of two clinicians (a senior and a junior orthopaedic trainee). The TMJ of these specimens was palpated and injected with 0.5mls aqueous jelly dyed with methylene blue. An independent investigator dissected the specimens and the location of the dye was recorded. A Posterior-Anterior radiograph was then taken to assess the bony anatomy of the joint and graded according to Eaton's classification.

Dye was found inside the joint capsule in 10 (83%) of the 12 specimens. Using Fishers Exact test no significant difference was found between the 2 injectors (p=0.46). The 2 joints where the dye was extra-articular had grade III and IV arthritis, whereas all other joints were graded I.

This study shows that good accuracy of TMJ injection can be achieved using palpation in the earlier stages of TMJ arthritis, when surface anatomy is accurate enough for an intra-articular injection. This is also when synovitis is more prevalent and injections are more relevant. However the failure rate of injections increases as the disease advances.

Blockade of the suprascapular nerve (SSN) with local anaesthetic is used frequently in shoulder surgery and for chronic shoulder pain. Anatomical landmarks may be used to locate the nerve prior to infiltration with local anaesthetic, but ultrasound is becoming a popular to locate the nerve.

Twelve cadaveric shoulders from 6 specimens were injected with dye using the landmark and ultrasound technique. The shoulders were scanned with computed tomography, and then dissected to ascertain the accuracy of each technique.

Using CT scan results, we found the ultrasound group to be more accurate in placing the anaesthetic needle close to the suprascapular notch, and therefore nerve, and this was significant (p = 0.0009). When analysing the ink data, although we did not observe a significant difference in amount of nerve covered by ink, we did note a correlation, and, given this study group is small, that may be considered a statistical trend.

This study, which is one of the largest cadaveric studies investigating landmark and ultrasound guided block of the suprascapular nerve and we believe the first to use CT, demonstrates that ultrasound guided block is significantly more accurate than the landmark technique, and would therefore recommend that ultrasound guidance be used when blocking the suprascapular nerve, given its higher accuracy and lower complication rate.

Treatment of syndesmotic injuries is a subject of ongoing controversy. Locking plates have been shown to provide both angular and axial stability and therefore could potentially control both shear forces and resist widening of the syndesmosis. The aim of this study is to determine whether a two-hole locking plate has biomechanical advantages over conventional screw stabilisation of the syndesmosis in this pattern of injury. Six pairs of fresh-frozen human cadaver lower legs were prepared to simulate an unstable Maisonneuve fracture. The limbs were then mounted on a servo-hydraulic testing rig and axially loaded to a peak load of 800N for 12000 cycles. Each limb was compared with its pair; one receiving stabilisation of the syndesmosis with two 4.5mm quadricortical cortical screws, the other a two-hole locking plate with 3.2mm locking screws (Smith and Nephew). Each limb was then externally rotated until failure occurred. Failure was defined as fracture of bone or metalwork, syndesmotic widening or axial migration >2mm. Both constructs effectively stabilised the syndesmosis during the cyclical loading within 1mm of movement. However the locking plate group demonstrated superior resistance to torque compared to quadricortical screw fixation (40.6Nm vs 21.2Nm respectively, p value <0.03).

Introduction

The treatment of Neer type 2 lateral end clavicle fractures presents a difficult problem due to the high incidence of non-union, delayed union, shoulder girdle instability and the need for implant removal. We report our experience in 10 patients with acute fractures treated with a simple modified tension band suturing technique.

Introduction: Injury to the distal third of the axillary artery is well recognised as a complication of proximal humeral fractures. However the risk of iatrogenic injury at shoulder surgery has not, to date, been fully appreciated.

Patients: Four female patients aged 59 and over who suffered iatrogenic injury to the axillary artery at the time of shoulder surgery are reported. Two occurred during surgery for planned elective shoulder arthroplasty, while two occurred while treating elderly patients who had previously sustained a 3 part proximal humeral fracture. In all 4 cases the injury probably started as an avulsion of the anterior or posterior humeral circumflex vessels.

Results: Vascular surgeons were called in urgently to help with the management of all 4 cases. In two cases the axillary artery was found to have extensive atheroma, was frail and, after initial attempts at end-to-end repair, it became clear that a reversed vein graft was required. Three patients had a satisfactory outcome after reconstruction, while one patient who had previously had local radiotherapy for malignancy, but was now disease free, developed a completely ischaemic upper limb and required a forequarter amputation to save her life.

Message: The axillary artery can be very frail in the elderly, is often diseased with atheroma, and is vulnerable to iatrogenic injury at surgery. If injury occurs at surgery, small bulldog clamps should be applied to the cut ends and a vascular surgeon should be called immediately. A temporary arterial shunt should be considered urgently to provide an early return of vascularisation to the limb and to prevent serious complications. The axillary artery is very difficult to repair, and, in our experience may require a vein graft. In addition, distal clearance of the main brachial artery with a Fogarty catheter which is an essential part of the management.

Clinician expectation and anatomical studies suggest that the distribution of sensory dysfunction in carpal tunnel syndrome (CTS) should be confined to the thumb, index, middle and half of the ring fingers. We mapped the distribution of disturbance to evaluate the accuracy of these assumptions.

We evaluated 64 wrists in 64 patients with nerve conduction study confirmed CTS. Each patient filled out a Katz hand diagram and we collated the distribution of pain and non-painful (tingling, numbness & decreased sensation) sensory disturbance. Frequency of reporting was analysed; dividing symptoms into thenar and hypo-thenar eminence, distal palm, each digit, posterior hand and forearm.

Non-painful sensory disturbance occurred in all patients. The index finger was the most common location (94%) followed by the middle finger (91%), the distal palm (84%), the ring finger (72%), the thumb (69%), the thenar eminence (63%), the little finger (39%), the dorsal hand (31%), the hypothenar eminence (25%) and the forearm (13%).

Pain was less common, reported in 59% of cases. Pain occurred most frequently over the wrist crease (33%) followed by thenar eminence (27%), the forearm (20%), the middle finger (23%), the index finger (22%), the ring finger (19%), the distal palm (16%), the thumb (14%), the dorsal hand (11%), the little finger (11%) and least frequently the hypothenar eminence (6%)

In CTS sensory disturbance occurs most frequently in the median nerve distribution; however it occurs almost as often elsewhere. An atypical distribution of symptoms should not discourage diagnosis of CTS.

The aim of the current study was to assess the amount of the distal humerus articular surface exposed through the Newcastle approach, a posterior triceps preserving exposure of the elbow joint.

24 cadaveric elbows (12 pairs) were randomized to receive one of the four posterior surgical approaches: triceps reflecting, triceps splitting, olecranon osteotomy and Newcastle approach. The ratio of the articular surface exposed for each elbow was calculated and compared.

The highest ratio observed was for Newcastle approach (0.75 ± 0.12) followed by olecranon osteotomy (0.51 ± 0.1), triceps reflecting (0.37 ± 0.08) and triceps splitting (0.35 ± 0.07). The differences between Newcastle approach and other approaches were statistically significant (p=0.003 vs osteotomy and < 0.0001 vs triceps reflecting and splitting).

The Newcastle approach sufficiently exposes the distal humerus for arthroplasty or fracture fixation purposes. Its use is supported by the current study.

Cement pressurisation in the distal humerus is technically difficult due to the anatomy of the humeral intramedullary (IM) cavity. Conventional cement restrictors often migrate proximally, reducing the effect of pressurisation during arthroplasty. Theoretically with a better cement bone interdigitation, the longevity of the elbow replacement can be improved.

The aim of this cadaveric study was to evaluate the usefulness of a novel technique for cementation.

Eight paired cadaveric elbows were used. The sides were randomly allocated to the conventional cementation group and pressurisation using a foley cathetre used as a cement restrictor. The cathetre was inserted into the IM canal after thorough washout and drying the cavity. The balloon inflated to act as a cement restrictor. Cementation was then performed and the cathetre removed just prior to cement setting. Radiographs of each pair was taken. Each distal humerus sample was cut in 1 cm increments starting from proximal part of the coronoid fossa. The slices were also radiographed to assess cement-bone interdigitation. The area of IM canal and the cement were calculated. The paired samples were compared.

The new technique consistently and significantly achieved a better cement interdigitation into the cancellous bone. The maximum penetration was observed in the proximal 1–3 cms from the coronoid fossa. According to previous studies, this area is the most common part involved in cement failure and loosening.

This study confirms the effectiveness of a foley cathetre as a cement restrictor. The ease of the technique and excellent pressurisation achived support its use.