Posterior Tibial Tendon Dysfunction

Indications

Patient must first fail nonoperative measures for a minimum of at least 3–6 months.
Stage I includes tenosynovitis without deformity that has been refractory to conservative treatment.
Stages II–IV includes painful deformity with medial and/or lateral foot pain.
- Lateral pain is classically subfibular impingement as the valgus hindfoot compresses the lateral structures.
- Note that in the later stages of disease, the patient may no longer complain of medial pain because of the chronicity of the posterior tibial tendon (PTT) tear.

Indications Pitfalls

Ensure radiographs are full weight bearing to accurately measure talar head uncovering on the anteroposterior (AP) projection.
Do not be fooled by congenital pes planus. Posterior tibial tendon dysfunction (PTTD) is an acquired, progressive deformity with specific etiology and treatment algorithms.
The deformity must be flexible (fully passively correctable on examination) to consider joint-sparing procedures.
- Rigid deformities must be managed with hindfoot arthrodesis.

Indications Controversies

Stage I: Is tenosynovectomy enough, or is transfer of flexor digitorum longus (FDL) necessary?
Stage II: When is a medializing calcaneal osteotomy necessary?
Stage IIb: When to pursue joint-sparing operations versus arthrodesis?
Stage III: Is a triple arthrodesis the only option?
Stage IV: Is a pantalar arthrodesis the only option?

What to look for:
- “Too many toes sign”
- Inability to perform a single heel rise
- Inability to bring the hindfoot into varus or neutral when standing on toes
- Pain along the PTT (especially around the medial malleolus)
- Subfibular impingement pain
- History of progressive foot deformity
Fig. 30.1 shows stage IIb PTTD seen on AP radiograph. Note the talar head uncovering and forefoot abduction.
Fig. 30.2 shows stage IIb PTTD seen on lateral radiograph. Note the loss of Meary line, calcaneal pitch, and medial cuneiform height (now more plantar than the base of the fifth metatarsal).

Treatment Options

Every operation includes a Silfverskiöld test with a gastrocnemius release or tendo-Achilles lengthening as necessary. This is performed first.
Treatment options traditionally follow the Johnson and Strom (1989) classification system:
Stage I: Tenosynovectomy
- We do not recommend FDL transfer
- Surgery is very rarely indicated for stage I
Stage IIa: PTT débridement
- FDL transfer
- Spring ligament repair versus reconstruction
- Medial displacement calcaneal osteotomy (MDCO)
- Possible Cotton procedure (opening wedge osteotomy of the medial cuneiform)
Stage IIb: PTT débridement
- FDL transfer
- Spring ligament repair versus reconstruction
- Lateral column lengthening
- MDCO
- Possible Cotton procedure (opening wedge osteotomy of the medial cuneiform)
- Possible peroneal brevis to longus tendon transfer
Stage III: Triple arthrodesis
- Rarely, isolated joint arthrodesis is possible
Stage IV: Pantalar arthrodesis
- May consider triple arthrodesis with deltoid ligament reconstruction
This procedure will focus on the surgical treatment options of stages IIa and IIb

Severely diseased PTT ( Fig. 30.3 )
Torn spring ligament ( Fig. 30.4 )
Peroneal tendons directly overlying the lateral column lengthening osteotomy site ( Fig. 30.5 )